Tuning-fork resonator with grooves on principal surfaces

Abstract

A resonator having a base part; and a resonating arm that performs flexing vibration, the resonating arm part has two principal surfaces, a first groove provided on the one principal surface, a second groove provided in juxtaposition with the first groove on the other principal surface, a third groove provided in juxtaposition with the first groove and provided nearer the base part side than the first groove on the other principal surface, and a fourth groove provided in juxtaposition with the second groove and provided nearer the base part side than the second groove on the principal surface. The sum of a depth of the first and second groove part and a sum of a depth of the third and fourth groove part are larger than a distance between the one principal surface and the other principal surface.

1. A resonator element comprising:
 a base part; and 
 two resonating arm parts that extend from the base part in a first direction and perform flexing vibration, 
 wherein each of the resonating arm parts has one principal surface and the other principal surface opposed to the one principal surface, 
 a first groove part provided along the first direction of the resonating arm part on each of the one principal surface, 
 a second groove part provided in juxtaposition with the first groove part in a second direction orthogonal to the first direction in a plan view on each of the other principal surfaces, 
 a third groove part provided in juxtaposition with the first groove part in the first direction in the plan view and provided nearer the base part side than the first groove on each of the other principal surfaces, and 
 a fourth groove part provided in juxtaposition with the second groove part in the first direction in the plan view and provided nearer the base part side than the second groove on each of the principal surfaces, and 
 wherein a sum of a depth of the first groove part and a depth of the second groove part and a sum of a depth of the third groove part and a depth of the fourth groove part are larger than a distance between the one principal surface and the other principal surface. 
 
     
     
       2. The resonator element according to  claim 1 , wherein, given that lengths of the first groove part and the second groove part in the first direction are RS and lengths of the third groove part and the fourth groove part in the first direction are S, S:RS=1:(2.2 to 2.8). 
     
     
       3. The resonator element according to  claim 1 , wherein, given that lengths of the first groove part and the second groove part in the first direction are RS, lengths of the third groove part and the fourth groove part in the first direction are S, a length from a base to a distal end of the resonating arm part is A, and a sum of RS and S is L, 8.8992×(L/A) 2 −3.3784×(L/A)+1.746≦RS/S≦1.3102×(L/A) 2 +3.3784×(L/A)+0.854. 
     
     
       4. The resonator element according to  claim 3 , wherein RS/S=5.1047×(L/A) 2 −9×10 −14 ×(L/A)+1.3. 
     
     
       5. The resonator element according to  claim 1 , wherein the resonator element contains quartz. 
     
     
       6. A resonator using the resonator element according to  claim 1 , comprising:
 the resonator element; and 
 a package housing the resonator element. 
 
     
     
       7. An oscillator using the resonator element according to  claim 1 ; comprising:
 the resonator element; and 
 a circuit device that drives the resonator element. 
 
     
     
       8. An electronic apparatus using the resonator element according to  claim 1 . 
     
     
       9. The resonator element according to  claim 1 , wherein the two resonating arm parts include a first resonating arm part and a second resonating arm part. 
     
     
       10. The resonator element according to  claim 9 , wherein the first resonating arm part includes a first surface disposed substantially perpendicular to the principal surface and the second resonating arm part includes a second surface disposed substantially perpendicular to the principal surface. 
     
     
       11. The resonator element according to  claim 10 , wherein the first surface is substantially parallel to and opposes the second surface. 
     
     
       12. The resonator element according to  claim 11 , wherein each of the first resonating arm part and the second resonating arm part includes the first groove and the second groove. 
     
     
       13. The resonator element according to  claim 12 , wherein the second groove of the first resonating arm part is disposed next to the first surface and the second groove of the second resonating arm part is disposed next to the second surface. 
     
     
       14. The resonator element according to  claim 12 , wherein the second groove of the first resonating arm part is disposed next to the first surface and the first groove of the second resonating arm part is disposed next to the second surface. 
     
     
       15. The resonator element according to  claim 12 , wherein the first groove of the first resonating arm part is disposed next to the first surface and the first groove of the second resonating arm part is disposed next to the second surface. 
     
     
       16. The resonator element according to  claim 12 , wherein the first groove of the first resonating arm part is disposed next to the first surface and the second groove of the second resonating arm part is disposed next to the second surface.